The goal of the Pigmented Lesion Clinical/Pathology Core (PLCC) is to provide efficient access to and use of the multiple clinical and pathology resources required to support the proposed projects. The PLCC is composed of three components, each of which provides critically important material and resources for the program. These are: 1) the Pigmented Lesion Clinic (PLC), a research-oriented multispecialty clinic specializing in the care of patients with melanoma and/or dysplastic nevi. 2) A comprehensive research pigmented lesion/melanoma Database, a data collection system and database that contains extensive clinical, pathologic, and tumor progression data on patients with a diagnosis of melanoma who have been seen by the PLC, and 3) A Melanoma Pathology Facility, with established procedures for the prospective accrual of research pathology specimens, an established archive of melanoma pathology slides and blocks, and established expertise in the performance and interpretation of diagnostic and research melanocytic pathology. The PLCC will provide the following services to the projects: 1. The Pigmented lesion/melanoma Clinic will: a. Provide the clinical setting and resources required to maximize accrual and compliance for the proposed studies, b. Accrue research subjects, c. Administer research related questionnaires and abstract data from patient records, and d. Coordinate accrual and distribution of blood specimens, clinical materials, and associated information for individual projects and for the PLCC's pathology Facility and Database. 2. The pigmented lesion/melanoma Database will: a. Collect, record, and maintain data on prospectively accrued patients with melanoma, b. Collect, record, and maintain follow-up data on patients in the established database, and c. Maintain data linking patients with their pathology and biologic materials. 3. The Melanoma pathology Facility will: a. Provide access to an archive of pathology slides and blocks from over 3,000 retrospectively accrued cases of melanoma, b. Provide prospective accrual of lesional material for immunohistologic and RNA in situ hybridization studies, and c. Provide technical expertise in these specialized pathology techniques and interpretation of complex tissue sections.